Almost all modern Mac computers—including all Apple Silicon M1, M2, and M3 models—use Solid-State Drives (SSDs) rather than mechanical HDDs. SSDs do not have moving parts; they read data electronically from flash memory cells. Because the access time to any flash memory cell is virtually instantaneous, file fragmentation does not degrade performance on an SSD. Defragging an SSD Shortens Its Lifespan

Offers "Compact," "Metadata," and "Full Optimization" to suit different needs. [1]

If you feel your Mac is running slowly or you are running out of space, skip the risky license keys and use these modern, safe alternatives:

Which of the four would you like?

You can find legacy versions on MacUpdate or similar archives. [2]

If you are using a relatively modern Mac, you iDefrag or any other defragmentation software.